Problem: A square with side length $s$ has an area of $225$ square centimeters. The following equation shows the area of the square. $s^2 = 225$ What is the side length of the square in centimeters?
Explanation: Let's solve for $s$. Remember that it is not possible to have a negative side length! $ $ $\begin{aligned} s^2 &= 225\\ \\ \sqrt{s^2} &= \sqrt{225}\\ \\ s&= 15 \end{aligned}$ The side length of the square is $15 \text{ cm}$.